1. Field of the Invention
The present invention relates to a method of manufacturing an olefin (hereinafter, may be referred to as “a light olefin” or “a light olefin having 2 to 4 carbon atoms”) having 2 to 4 carbon atoms using a Fischer-Tropsch reaction.
Priority is claimed on Japanese Patent Application No. 2012-178548, filed on Aug. 10, 2012, and Japanese Patent Application No. 2013-040105, filed on Feb. 28, 2013, the contents of which are incorporated herein by reference.
2. Description of Related Art
As a method of synthesizing hydrocarbons from synthesis gas (i.e., mixed gas containing carbon monoxide and hydrogen as the main components), a Fischer-Tropsch reaction is known. The Fischer-Tropsch reaction may include, for example, a reaction in which straight-chain saturated hydrocarbons are generated from synthesis gas (CO+H2) using a cobalt-based catalyst as a metal catalyst. The reaction formula at this time is as follows.nCO+(2n+1)H2→CnH2n+2+nH2O
In the related art, the objective product of synthesis of a hydrocarbon from synthesis gas through the FT reaction is a saturated hydrocarbon in most cases. The saturated hydrocarbons are further subjected to various processes such as hydrocracking and isomerization and then are used as fuels or lubricating oils. On the other hand, in the Fischer-Tropsch reaction in which an iron-based catalyst is used, there may be cases where unsaturated hydrocarbons are generated along with the saturated hydrocarbons. However, the selectivity of the saturated hydrocarbons is very low. Therefore, in general, the unsaturated hydrocarbons are converted into saturated hydrocarbons through hydrogenation or the like.
On the other hand, light olefins such as ethylene, propylene, and butene are widely used as raw material compounds in the chemical industry. Particularly, propylene is a useful and important compound as a starting material, for example, in the manufacture of polypropylene.
Hitherto, as the Fischer-Tropsch reaction which aims to manufacture light olefins, a method in which an iron-based catalyst in which a manganese-based compound is contained as a support (refer to Patent Literatures 1 and 2), and a method in which a catalyst which is obtained by carrying iron, copper, and potassium in a silica porous support is used (refer to Patent Literature 3) are disclosed.